


20 Days of Chub: Size Comparisons

by Star_Sniper



Series: 20 Days of Chub: Eren/Armin [7]
Category: Shingeki no Kyojin | Attack on Titan
Genre: Belly Kink, Chubby armin, High School AU, M/M, Modern AU, Weight Gain, fat armin, fat kink
Language: English
Status: Completed
Published: 2017-10-01
Updated: 2017-10-01
Packaged: 2019-01-07 17:14:26
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,269
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12237213
Author URL: https://archiveofourown.org/users/Star_Sniper/pseuds/Star_Sniper
Summary: Modern AU: Eren contemplates the differences between Armin and himself. Eren is dark haired, Armin is fair, Eren is tall, Armin is short, and while Eren is in the best shape of his life, Armin has always been chubby.Eren loves it.[20 Days of Chub taken from the20 Days of Chub Challenge.]





	20 Days of Chub: Size Comparisons

The balmy heat of summer had continued on long into the evening, so Eren had driven himself and his best friend down to the river. They had the little fishing dock to themselves at that time of night, with only clouds of hovering fireflies for company. Eren rolled his pant legs up to his knees, and sat on the very edge of the wooden pier to dangle his legs into the blissfully cold water. He leant back on his arms, a long sigh gusting over his lower lip. He felt the boards of the jetty creak as Armin joined him, his thigh brushing up against Eren's, and flashed a grin over at his best friend. Armin returned it with a shy smile, his rounded cheeks dimpling in the twilight. 

They couldn't have looked more different, Eren noted as Armin returned his gaze out over the water; the blond had a deep fascination for all bodies of water, and had done ever since Eren had first met him at the tender age of just seven years old. While Eren was dark haired and tanned, Armin was fair and pale. Eren was tall and lean, with fine lines of muscle rippling underneath his skin. Armin was short and plump, with a round stomach that protruded out against the front of his shirts. Armin had been chubby for as long as Eren could remember, and it had never bothered him in the slightest; it was just who Armin was. It was a much a part of him as his blue eyes or slightly snubbed nose. 

“Can't believe it's going to be our last year of high school,” Eren admitted after a moment of peaceful silence between them, “Crazy, isn't it? Then we got college, university, real life-ugh!” he flopped down onto his back, his gaze up on the pink streaked sky above them, “I don't think I'm ready to grow up yet. I don't want to have to be all responsible and mature.”

“But you get more freedom with more responsibility,” Armin tilted his head to look down at Eren, tendrils of hair clinging to his clammy cheeks, “And I think that you still have a few years to be, well, _you_.”

“With great responsibility, comes great freedom?” Eren snickered, tucking his arms up behind his head, “Don't try to 'Uncle Ben' me. Doesn't it bother you that we've only got one more year left at school?” 

“No,” Armin admitted, “There's some people I'll miss, but I'm looking forward to going to college. I'm not exactly popular,” his cheeks coloured self consciously, “At least people in college will just be there because they want to learn, not because they have to be there.” 

Eren winced the moment Armin turned away. He had never had problems making friends, despite the fact that he was impatient and very quick to anger. Eren knew that a large part of it was due to the fact he had grown up to be tall, pushing just under six foot, and handsome. But Armin, quiet and withdrawn Armin had always struggled when it came to other students. He had a few friends, most of which he shared with Eren, but he was also a prime target for bullying. Eren sat up, just enough to wrap his hand about Armin's soft upper arm, and pulled him down to lie next to him on the wooden planks. 

“It's gonna be weird not getting to see you every day,” Eren looked across at Armin, “Who else is going to reluctantly lend me their notes? Who else is going to help me when my laptop is refusing to do that _thing_ again? Who else is going to understand that I just can't function until after my energy drink?” 

Armin's laugh was music to Eren's ears. “I'm glad that I'm useful for something?”

“I mean it,” Eren protested, rolling onto his side, propping his head up against the palm of his hand, “I'm really gonna miss you. I've seen you almost every single day for the past, what,” he raised his eyes skywards in thought, “- ten years? That's longer than I've known my own sister.”

“I'm going to miss you too,” Armin responded quietly, shifting onto his side to face Eren directly, “More than you'll ever know.” His protruding belly filled the gap between them, the crest of it brushing against Eren's toned abs. It felt warm and full through the thin material of both Eren and Armin's t-shirts, and Eren felt a small spasm of pleasure on feeling the heat of Armin's skin against his own. 

“Think we'll still meet up at the start of every summer and come down to the river?” Eren teased, but there was a small amount of hope in his tone; he wanted to continue this tradition of theirs more than anything, “Even when you'll be taking off your lab coat so the ends don't get wet, and I'll have to keep my cleats in the car, 'cos a crazed fan might steal them when we're not looking?”

“You're going to come down here in your football uniform?” Armin's eyes creased with mirth, “I don't think that the Sina Titans are going to be too pleased with that.”

“They're the ones that recruited me at the tender age of seventeen,” Eren reminded him, pride swelling in his chest, “Besides, it'll be good publicity for them. Somehow.”

“Somehow,” Armin repeated with a smile, “I don't think I'll be wearing my lab coat down here, either. They're not exactly keen on you taking them outside of the laboratory. It sort of defeats the purpose of having a _lab_ coat in the first place.”

“So we'll just be down here in our civvies instead,” Eren decided with a nod, “I dunno if I'll want to drive my Ferrari all the way down here, so we might have to go in your car. What do you think, Armin? Mercedes? BMW?”

“I think that you're underestimating just how much money I'll be making,” Armin corrected him, his lips twitching into a smile, “We'll just have to go in your second car instead.”

“The Bentley it is,” Eren grinned, “Though we might run into a similar problem. I'll just have to have a third car that I don't mind leaving out in the middle of no-where. Just a Porsche or something. One for slumming it.” 

For a moment they just led there, facing one another with the kind of openness that came with over a decade of friendship. Eren rarely hid anything from Armin, he could tell him things that he just couldn't tell his parents or sister. Armin's opinion was always the first one that he sought, the blond had a way of both being honest and kind in the same breath. He could tell Eren that his idea to become a worldwide rock star at the age of eighteen wasn't going to happen, but that he should focus on football, something that he had been incredibly talented at for a number of years. 

“Oh, um,” Armin seemed to be suddenly aware of how much room he was taking up, compared to Eren, and he sucked his stomach in with an ashamed duck of his head, “Sorry. Do you have enough room...?” 

“I've got more than enough room,” Eren reached out to pat Armin's rounded side affectionately, “Don't hold back on my account. 'Sides, you're not nearly as big as you think you are.” Sometimes Eren got the impression that Armin thought he was massive, when the reality as that he was chubby, just bordering on being a little bit fat. He felt a surprising shiver soak his spine as Armin exhaled again, the curve of his stomach pushing up gently against the palm of Eren's hand. 

Oh, Eren realised as that shiver ended with a pulse of pleasure around his groin, he had severely underestimated just how much he liked that. 

“I'm big compared to you,” Armin pointed out with a rueful smile, “You know you don't have to tiptoe around it, Eren. I'm fat. I always have been, and given my complete and utter lack of self-will, I always will be.” 

“Yeah, well,” Eren attempted casually, “You say it like it's a bad thing.” 

Armin's eyes widened in genuine surprise. “What?” 

His friends and family had often teased Eren about how dense he was. Eren was smart, though not quite along the same lines as Armin and Mikasa, but he had the habit of being just a little simple at times. Eren didn't see things until they were staring him right in the face, and even then he would have to take several moments to actually process what it was that he was seeing. Eren had always put it down to the fact that he didn't tend to overthink anything, he was far better at thinking on his feet, which was why he was such a talented and highly valued football player. 

But even Eren was shocked on discovering that it had taken him this long to realise he had a crush on his best friend. 

“Look, Armin,” Eren ran his hand over the back of his neck, “You're cute, you're kind, and you're crazy-smart. You're always looking out for people, and you're always trying to make the world a better place, even if you are a pain in the ass when you make me put my garbage in the right recycling bin.”

“Eren-” Armin began uncertainly, but Eren silenced him with a shake of his head. 

“Not finished. Armin, you're one of the best people I know,” Eren could feel his face growing warm, “A-and it's adorable that you're a bit chubby. I like it,” he swallowed, nervous from both his confession and the realisation that he really did like Armin's softer form, “I really like it.”

Armin stared at Eren for what felt like an eternity. “You like me?”

“Yes,” Eren exhaled loudly, releasing a breath he hadn't known he had been holding onto, “I like you. Like-like you. Is that what the kids are saying these days?”

“We are the kids 'these days',” Armin reminded Eren with a giggle, before sobering as he met Eren's gaze, “You really mean it?” 

“I think I've like-liked you for a really long time now,” Eren confessed, memories of the countless hours that he and Armin had spent together hovering at the forefront of his mind, “I was just too dumb to realise it.” 

“You're not dumb,” Armin corrected automatically, before softening his tone, a pink blush dusting his rounded cheeks, “I like-like you too. I just thought that someone like you-”

“Don't even say it,” Eren interrupted, spreading his hand over Armin's mouth, “I don't want to hear you put yourself down again.”

Armin's breath was warm against the palm of Eren's hand as he nodded. “Okay. I'm sorry.” 

Eren's heart was pounding in his chest. He felt dizzy with relief, but his stomach was fluttering anxiously underneath the loose folds of his tank top. Realising and then acting upon a crush in the space of five minutes had left him emotionally shaken, and all he could think about was the fact that Armin liked him back. Their entire relationship had changed in the blink of an eye, and while Eren felt a little uneasy about what it meant for their friendship, he couldn't stop the elated feeling racing through his veins. 

“I've never done this before,” Armin chewed on his lower lip, “What happens now?”

“Don't overthink this,” Eren inched his way closer to Armin, until their upper bodies were pressed up against one another, “I find that it's always better to just, you know, go with the flow. As the kids say.” 

With that, Eren pressed his lips to Amin's. 

Armin's lips tasted like suncream, and were even softer to the touch that Eren could have ever imagined. Eren placed his hand against Armin's cheek as he deepened the kiss, coaxing the blond by running his tongue along the seam of those plump lips. He lowered his fingers down over Armin's soft jawline, tracing the curve of his neck. Armin murmured into the kiss, his lips parting obediently under the tip of Eren's tongue. Eren felt his way down Armin's chest, the palm of his hand resting against the upper curve of his belly. 

Between kisses, Armin's confidence steadily grew. He reached out, his arm brushing across Eren's in order to rest his hand at the sharp nip of Eren's narrow waist. Eren grinned into their next kiss, he could feel Armin's fingers spread out across his defined stomach, not so subtly feeling his firm abdominal muscles. Eren stroked his way over Armin's rounded sides, marvelling at the swell of his lovehandles, poking out playfully over the top of Armin's jeans. He pinched one between finger and thumb, and was rewarded as Armin gasped into the kiss. 

Eren slid his leg between Armin's thighs, his breath catching in his throat at how soft and heavy they felt. They weren't that much bigger than Eren's own thighs, but while his were strong planes of firm muscle, Armin's were as pudgy as his belly. Eren groaned low in his throat, there was something so oddly satisfying about feeling Armin's chub press up against firm muscle. There was something so exhilarating about comparing Armin's plush figure against his own. Eren hooked his leg around the back of Armin's knee, pulling him in even closer.

“I meant what I said,” Eren murmured as they both broke back for air, “I like that you're a little soft. Just means there's more of you to appreciate.” 

“Th-that's so cheesy,” Armin panted, his warm breath tickling Eren's lower lip, “But sweet.”

Eren effortlessly pushed himself to sit back up, rubbing at where his cheek had been pressed against the dock. He watched as Armin followed suit, with some effort due to the prominent swell of his belly. Eren had always felt as if he knew Armin inside and out, but now that he was looking at his best friend, truly looking at him, he could see all sorts of little details that he had glossed over before. Like how Armin had freckles, very pale freckles, that were scattered across his upper cheeks and nose like a star constellation. Or how his eyelashes were so dark and thick compared to his fair hair, long enough to brush against his rounded cheeks whenever he closed his eyes. 

Or, Eren swallowed as he stared at Armin's profile in the twilight, how Armin's stomach was large enough to rest on the very tops of his thighs when he was sat upright. Eren glanced downwards, at his own flat midsection. He found himself wondering what it felt like, to have your downward vision obstructed by your own girth. His gaze flickered back across to Armin, pleasure pulsating behind his groin as he followed the curve of his belly with his eyes, drinking in the way it pushed against the front of Armin's t-shirt. 

Realising that he had a thing for his best friend was one thing, Eren decided with an internal sigh, but discovering that he had a thing for chubby guys in the same moment was almost unfair. 

“You really like this?” Armin's quiet question pulled Eren out of his thoughts, “You like that I'm fat?” 

“Shit,” Eren hissed between his teeth, “Yeah. Does it bother you?” 

Armin furrowed his brow, his brilliant blue eyes creased in thought. “No. Not really. I don't quite _get_ it, but it doesn't bother me.” 

“It's, like-” Eren faltered for a moment, “You like that I'm in shape, right? And don't give me none of that 'I like you for you, Eren' because I felt you feeling up my abs back there.”

“It's not the defining reason why I like you,” Armin began slowly, but there was no disguising the flush on his cheeks, “But there is something really nice about how strong you are. Sometimes I can see your muscles moving under your skin and-,” he cut himself off with a shy smile, “And it just does something to me on a purely primal level.”

“See?” Eren gestured, trying and failing to squash the swell of pride building in his chest at Armin's words, “It's kinda like that.” 

The sun had finally sank below the horizon, the balmy summer heat replaced with a damp chill. The streaks of violet overhead had darkened to a midnight blue, set against an inky black sky. The sky was so clear, free from clouds and light pollution, that the stars sparkled like diamonds overhead. The moon was wasn't quite full, Eren couldn't recall the exact term for it, but still shone brightly at them from behind the trees. 

Beside him, Armin pulled out his phone, inhaling sharply on noticing the time. “ _Oh-no_. I need to get going. Dad said I needed to be back before nine.” 

“Nine?” Eren repeated in some surprise as he stood up, “It's that late already?”

“Almost,” Armin peered at his gently glowing phone screen, “It's about twenty to. I might be being a little overcautious, but I don't want to get grounded before the summer even starts.” 

“Don't worry about it,” Eren reassured him, resting his hand against Armin's lower back, “I know what a hard ass your old man is.” 

“He's actually quite fond of you,” Armin's smile grew sheepish, “In his own way.”

Eren snorted as he guided Armin off the dock and back onto the grass. It wasn't that Armin's father was inherently a bad person, he couldn't have been given that he had adopted Armin at just five years old. It was more that he was stern and overprotective, and was absolutely terrifying despite his diminutive size. Levi was even shorter than his own adopted son, and Armin wasn't exactly that tall for his age. Eren slipped his arm around Armin's waist as they began the short walk back to the car, his fingers sinking against the soft roll of fat that had settled there. 

“He's gonna hate me if he finds out that I kissed you,” Eren chuckled easily, though he felt a small pang of terror at the thought of Levi finding out he had defiled his beloved son, “If he finds out, I guess. It's your call, Armin. You know him better than I do.” 

“Maybe,” Armin began diplomatically, “We should see how this goes. If we're still together at the end of the holidays, we could think about telling him then? I mean,” he hesitated, his thick brows knitting together, “We are together, aren't we?” 

“We are now,” Eren confirmed, with an affectionate squeeze of Armin's waist, “Sounds like an idea to me. But, and call me a sap for thinkin' this, I think we're gonna be together for every summer for the rest of our lives.” 

“Sap,” Armin leant against Eren's side, his cheek pressed up against his chest, “We can come back every summer. You without your cleats, me without my lab coat. We can sit on the dock again, and remember every last detail about this night.” 

Eren couldn't help but agree as he watched the way that Armin's thighs brushed against one another as he walked, compared to Eren's own thigh gap. At the way Armin's belly bounced ever so slightly over the uneven patches of ground, while Eren's firm abdominal muscles remained solid and unmoving. And the fact that Armin was slightly breathless before they reached the car, while Eren had barely broken a sweat. 

He wasn't going to forget this summer for as long as he lived.

**Author's Note:**

> Can't believe I've not posted for just under a year. 
> 
> I have a lot of ideas on the go right now, so here's hoping something comes out of all the half-finished ideas I have written. 
> 
> Thank you for being so patient!


End file.
